Abstract

A problem common to many studies involving the use of unsaturated flow and chemical models is determining a representative expression for the value of unsaturated hydraulic conductivity K(ψ). A new steady-state inverse methodology called the multi-step steady-state outflow method (MSSOM) is presented here for the determination of unsaturated hydraulic conductivity. The method offers a practical alternative for the estimation of K(ψ) using either the exponential model, three-parameter model, or the van Genuchten formulations for K(ψ), a global-optimization simplex routine (MSSOM.EXE), and simple outflow data from a one-dimensional column experiment. The inverse technique was applied to a coarse sand and both the wetting an drying curves were well within the range of K(ψ) expected. Conductivity data from four other soils in the literature were then fitted using a curve fitting routine (RETC.F77) by van Genuchten, 1985 and compared to the inverse solution from the MSSOM model. The parameters for the K(ψ) expressions from both RETC and the MSSOM inverse model agreed well. Additional refinement of the multi-step steady-state outflow laboratory apparatus and the optimization program MSSOM.EXE are needed however to further improve the method.

Export search results

The export option will allow you to export the current search results of the entered query to a file. Different
formats are available for download. To export the items, click on the button corresponding with the preferred download format.

By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export.
The amount of items that can be exported at once is similarly restricted as the full export.

After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.